End to end scale up/out support added.
1. Command line tool to manually send scale up/out signal to a particular app, for a given pellet name.
2. Resource manager interface (A simple ClusterResourceManager implementation) to handle scale up requests.
3. ResourceMappingDelta - new class to provide simple access to the resource changes for the individual container.
4. Updated AppsAssignmentMonitor to respond to the updated resource mapping. (by creating new pellet instances (and flakes) as required, connecting new flakes to predecessor flakes and also connecting current flakes to new predecessor flakes that might have been created).

Note: No active load balancing yet. Message distribution is currently handled by the ZMQ push/pull mechanism.

This also lays some ground work for the scale in/down feature.

Tested on a psuedo-distributed setup.

Fixes #3
Merge branch 'master' of https://github.com/usc-cloud/floe2